NASA's Mars Reconnaissance Orbiter has revealed that movement in sand dune fields on Mars occurs on a scale similar to dune fields on Earth. This was unexpected because Mars has a much thinner atmosphere than Earth (it is only about 1% as dense) and its high-speed winds are less frequent and weaker than Earth's. Scientists using HiRISE images have determined that entire dunes as thick as 200 feet are moving as coherent units across the Martian landscape. The animated GIF above shows a rippled dune front in Herschel Crater on Mars moved an average of about two meters between March 3, 2007 and December 1, 2010. A larger version of the animation can be found here
Doug McCuistion, director of NASA's Mars Exploration Program in Washington, says, "This exciting discovery will inform scientists trying to better understand the changing surface conditions of Mars on a more global scale. This improved understanding of surface dynamics will provide vital information in planning future robotic and human Mars exploration missions."
Scientists will use the information to understand broader mysteries on Mars, like why so much of the surface appears heavily eroded, how that occurred, and whether it is a current process or it was done in the past. Scientists can now point to sand flux as a mechanism capable of creating significant erosion today on the Red Planet.
You can see more animations of sand dunes in motion on Mars here
Photo: NASA/JPL-Caltech/Univ. of Ariz./JHUAPL